A reddit thread interested me while I wound up my day for work, so I wrote this.

revPrimes.py

# inspired by this post, an a general curiousity...
# https://www.reddit.com/r/math/comments/578drx/i_believe_ive_found_something_very_interesting/
# it seems that reverse binary primes actually get rarer the further you get

# http://stackoverflow.com/questions/2068372/fastest-way-to-list-all-primes-below-n/3035188#3035188
def primes(n):
    """ Returns  a list of primes < n """
    sieve = [True] * (n/2)
    for i in xrange(3,int(n**0.5)+1,2):
        if sieve[i/2]:
            sieve[i*i/2::i] = [False] * ((n-i*i-1)/(2*i)+1)
    return [2] + [2*i+1 for i in xrange(1,n/2) if sieve[i]]

# http://stackoverflow.com/questions/15285534/isprime-function-for-python-language    
def is_prime(n):
  if n == 2 or n == 3: return True
  if n < 2 or n%2 == 0: return False
  if n < 9: return True
  if n%3 == 0: return False
  r = int(n**0.5)
  f = 5
  while f <= r:
    #print '\t',f
    if n%f == 0: return False
    if n%(f+2) == 0: return False
    f +=6
  return True   

def binary(n):
  return bin(n)[2:]

def reverseBinary(n):
  return binary(n)[::-1]


def revPrimeRun(primeMax, quiet=True):
  allPrimes = primes(primeMax)
  revPrimes = []
  for prime in allPrimes:
    rb = reverseBinary(prime)
    value = int(rb, 2)
    isPrime = is_prime(value)
    if isPrime:
      revPrimes += [(prime, value)]
      
    if not quiet:
      print "%d, %s, %s, %d, %s" % (prime, binary(prime), rb, value, str(isPrime))

  if not quiet:    
    print "Number of Primes < primeMax:", len(allPrimes)
    print "Number of RevePrimes:", len(revPrimes)
    print "rev/all", len(revPrimes)/float(len(allPrimes))
  return (len(revPrimes), len(allPrimes))


revPrimeRun(1000, False)

v = []
for a in range(100, 100000, 1000):
  revPrimes, allPrimes = revPrimeRun(a)
  v += [float(revPrimes) / allPrimes]
  
print v